Secondary high explosives, including the nitramines RDX, HMX, and CL-20, are typically used in their common crystalline states. In order to alter their explosive properties including energetic performance and sensitivity to inadvertent initiation, parameters including the crystal size, crystal polymorph, and crystal quality are often varied.
A known alternative to the solid crystalline form of organic materials is an amorphous (aka glassy) state. A key distinction between these two forms/states, is that in the glassy state the constituent molecules are arranged in a highly disordered manner, while in crystalline materials the molecules have long range ordering. Due to the disorder in the molecular arrangement, amorphous materials inherently contain additional specific energy versus crystalline forms—as a result of the strained arrangement of the molecules. In such a “strained” form, materials typically exhibit drastically differing physical properties when compared to the crystalline form. These different physical properties are often characterized by: significantly lower thermal conductivity; optical transparency; and liquid-like viscous flow above the glass transition temperature (Tg). Further, due to the stored strain energy in the amorphous material, reaction of such materials can potentially be faster and more exothermic than in the crystalline form. So, while it would appear that amorphous materials have some potential advantages over crystalline materials for use as explosives—due to the higher Gibbs free energy inherent to the amorphous state relative to the crystalline state, there is a general tendency of amorphous materials to crystallize. This is a major obstacle encountered in numerous fields including pharmaceuticals and often hinders transitioning of amorphous materials to end items.
Therefore, there is a need in the art for secondary explosive materials that are in an amorphous state that is stable—such that the subject explosive materials will exhibit desirable properties not available in such materials that are in their crystalline forms.